In the past few months I have noticed a problem with some of the routes where the GPS signal would drop out and randomly lose its accuracy when recording the rides on the GoPro.

At the time I thought it was due to parts of the rides being under trees which can cause signal issues but after trying to record a ride last week on open roads and the Garmin not being able to get a GPS lock I removed the Gamin from the bike and walked a few meters away and the signal reappeared with a GPS lock in a few seconds.

I then turned off the GoPro and found that the Garmin then worked on the bike, turning the GoPro back on again caused the Garmin to completely lose the GPS lock confirming the source of the GPS problems.

A search online found a lot of other people who had similar problems both with bike computers and also a lot of UAV / Drone users who had major GPS issues when recording using a GoPro camera causing their drones to lose GPS lock and even crash.

I found this template guide for a EMI shield for the GoPro Hero 3 designed by http://www.hovership.com/ which I printed mirrored on to a sheet of self-adhesive paper and then stuck it onto the back of a sheet of self-adhesive copper sheet which I purchased from eBay. We cut the template out of the copper sheet with a craft knife and fitted it to the GoPro.

Copper sheet cutout ready to be fitted to the GoPro.

The completed copper EMI shielding

External battery pack fitted

The finished shielded GoPro Hero 3 in the waterproof case.

Once the copper shielding was fitted to the GoPro we tested it again with the Gamin Edge 810 and found that the interference was almost completely eliminated as you can see on the video below.

We also shielded the back of the waterproof case using copper leaf which Andrew had purchased to use on one of his model ships.

The copper leaf was more difficult to apply to the plastic case and so we decided to only shield the back cover rather than trying to glue the leaf on the front half of the case as well.